In 2016, the communist government of Cuba carried out "acoustic attacks" on United States diplomats in Cuba. The CNN newspaper writes in a publication about what happened with the attacks, I quote it below:

What happened behind the "acoustic attacks" experienced by U.S. government personnel in Havana, Cuba, beginning in late 2016 remains a mystery, but a new study released Tuesday looks for clues in the brains of workers who were exposed to them.

MRI brain scans of 40 patients — 23 men and 17 women — showed variations in brain structure and functional connectivity, which measures relationships between different brain regions, compared to 48 other adults. The scans were taken between August 2017 and June 2018.

"There were group differences throughout the brain," said study author Ragini Verma, a professor of radiology and neurosurgery at the Perelman School of Medicine at the University of Pennsylvania. "Especially in an area called the cerebellum, which is also involved in the type of clinical symptoms that most of these patients were demonstrating, which are balance, eye movement, dizziness, etc."

According to the study, differences in connectivity were also observed in the auditory and visuospatial areas of the brain. However, the authors note that the clinical significance of these findings is uncertain, and that they did not have previous MRI scans of the patients to compare how their brains looked before the incidents.

Most patients reported problems with memory, concentration, balance, vision, hearing, sleep or headaches that lasted more than three months.

Many reported feeling "mentally foggy" or "slowed down" for months, the authors said. Some reported irritability and nervousness, with two meeting criteria for post-traumatic stress disorder. Poorer job performance was also observed.

Three people eventually needed hearing aids for moderate to severe hearing loss, and others had ringing or pressure in their ears. More than half needed to be prescribed a medication to help them sleep or treat headaches. Many were unable to return to work, at least for a period of time.

The New York Times suggests in a publication that whether the presentation reflects physical damage from an enigmatic weapon or something else is still far from clear, the authors acknowledged. Reaching a firm conclusion would likely require many more cases, a situation no one is expecting to encounter.